An Extreme Temperature Weekend in Western North America


There were some absolutely amazing diurnal temperature variations over the weekend. Puntzi Mountain, BC (elevation: 910 m) was -8°C Friday afternoon, and then -36.5°C Saturday morning — a 28.5°C drop. Keep in mind that the LARGEST overnight temperature drop at Puntzi Mountain last year was 27.5°C!

The temperature rose to -6.7°C Saturday afternoon — a 29.8°C rise. Keep in mind that the LARGEST daily temperature rise at Puntzi Mountain last year was 28.9°C!

Then the temperature dropped 26.9 degrees to -33.6°C Sunday morning before rising 27.7 degrees to -5.9°C. Then, it dropped an astounding 30.7°C (55°F) overnight to -36.6°C! Keep in mind that the highest overnight temperature drop in BC in 2017 was Merritt when the temperature dropped 29.6°C in August.

Alberta saw even more extreme temperature swings.

Here are the top three:

  1. Hendrickson Creek (1,448 m): a 24 hour change of 38.7°C (-35.9°C in the morning and 2.8°C in the afternoon).
  2. Sundre (1,114 m) : a 24 hour change of 36.9°C (-39.2°C in the morning and -2.3°C in the afternoon).
  3. Claresholm (1,009 m) : a 24 hour change of 35.9°C (-34.1°C in the morning and 1.8°C in the afternoon).

These strong temperature swings were the result of very strong temperature inversions in the morning hours, and then enough sunshine and wind in the afternoon to break the inversion.

Further north, the sunlight is not intense enough to reverse the inversion by the afternoon this time of year, so inversions tend to be more extreme. Around Dawson, Yukon and Fairbanks, Alaska, the inversion was so strong over the weekend that surface was 60°F (33°C) colder than it was at 2900′ (900 m) above the ground. For Fairbanks, that’s -19°F (-28°C) at the surface and +41°F (5°C) at 2900′ above the ground.

An inversion this extreme is uncommon, but still not a record. That record was set in McGrath, Alaska on Jan 13, 1966 when the surface was 40°C (72°F)  colder than at 855 mb (1180 m above the ground). The surface temperature was -40.7°C (-41.3°F) versus -0.7°C (+30.7°F) at 855 mb.


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What Does it Take to Trigger an Extreme Cold Alert in Canada?


Much of the east coast of North America is under an extreme cold warning, so that provides an opportunity to add to our weather warning series.

TRIGGER WARNING: We are looking at the thresholds required to trigger weather warnings in Canada. (Previously, we have discussed wind, rainfall, snowfall, and heat.)

As with the rest of the weather extremes, Environment Canada changes the criteria depending on the location. Some of the differences do make sense, such as the assumption that those living in the south are complete wusses, so they will be issued an “extreme cold warning” some 35 degrees Celsius above that of the far north.

Some others are a little more confusing such as the fact that an extreme cold warning is not triggered in Vancouver and Victoria (Canada’s most mild cities) until the temperature or windchill is expected to drop down to -35°C, but in Windsor, Ontario a temperature or windchill of just -30°C will trigger the same warning.

The following map graphically represents the extreme cold threshold differences across Canada.





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Wind Warning Thresholds in Canada


Environment Canada has issued a wind warning for parts of British Columbia today. The red on this map shows the affected locations.


Now, this is quite interesting because the Vancouver and Victoria areas are under a wind warning while the west coast of British Columbia where winds are expected to be even stronger are not under a warning.

The reason for this difference is that Environment Canada has three different set points for triggering a wind warning across the country. The highest wind areas of British Columbia need 90km/h sustained winds and/or 110km/h gusts to trigger a warning.

Some of other windy locations in Canada (the west coast of Vancouver Island, the Dempster Highway in the Yukon, southwestern Alberta, and the Wreckhouse area of Newfoundland) will be issued a wind warning at 80km/h sustained winds and/or gusts of 100km/h.

The rest of the country has a lower wind warning threshold of 70km/h for sustained winds and/or gusts of 90km/h.


See also: Rainfall Warning Thresholds in Canada

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Rainfall Warning Thresholds in Canada

Previously we have discussed snowfall and heat warnings in Canada and how grossly inconsistent they are across the country.

Fortunately, Environment Canada is much more realistic when it comes to setting rainfall warning thresholds. Such warnings are season dependent, but for today’s exercise I am using “Table 14. Alerting parameters Environment Canada uses for issuing a Long Duration Rainfall Warning in the Summer.

Graphically, the table is represented as follows:


Unlike Environment Canada’s heat warnings, this map actually makes sense. Basically, the country is divided into three zones (excluding northern Quebec where warnings aren’t issued):

  1. The rainiest portions of coastal British Columbia.
  2. The British Columbia interior dry belt.
  3. The rest of Canada.
Posted in Climate, Geography | Tagged | 2 Comments

Was 2017 Really the Hottest July-August Ever in Kelowna, BC?


I saw this article today, and thought it was a bit strange that they would make this claim.

Typical of the media. They will tease you with some truthful facts, but just like a Donald Trump tweet, they don’t stop there. They can’t resist the temptation to add in some “alternative facts” to make the article click-bait material.

In short, the article makes two claims:

  1. 2017 was the driest summer on record (June-August).
  2. 2017 was the hottest July-August on record.

On the first point they are indeed correct. 2017 was by far the driest summer on record in Kelowna.

But Castanet could not stop there. It had to add in the temperature for good measure.

Both July and August established new benchmarks for temperature and precipitation, making them the warmest, and driest ever recorded.

However, it should be noted Kelowna records have only been kept since 1969. Data has been collected since 1908 in Penticton and 1900 in Vernon.

Environment Canada meteorologist Alyssa Charbonneau says the average temperature in August was 22.2 C, more than three degrees above the norm.

Given the reference to 1969, they would be referring to the airport since that’s when that station was first established, but every weather buff knows that the airport is located in a frost hollow where the cold air pools at night. While the daytime temperatures are similar to the surrounding parts of the city, the nighttime temperatures are on average three or more degrees cooler than other weather stations in and around the city.

When Environment Canada states that the July-August temperature was 22.2°C, they are referring to the mean temperature (the average between the daily highs and lows). Additionally, this figure is for the University of British Columbia Okanagan (UBCO) weather station, which records much warmer nights than the airport.

The second paragraph in the above quote implies that Penticton and Vernon didn’t set records because they have data from before 1969, but that’s not why. In fact, there are several recent years warmer than 2017 including 2003 and 1998. The only reason Kelowna was “warmer” in 2017 is that this article incorrectly compared a cold weather station from the past against a warm location from the present.

This would be equivalent to moving your city’s airport uphill 1,000 feet, and then claiming that you’ve had a cold summer because the temperature at the new location was cooler than the average of the old location.

There’s not a single weather station in the Okanagan that was warmer in 2017 than 1998, and that includes the airport.

The UBCO station is a new station, so it wasn’t around in 1998, but the airport station along with the Okanagan Centre station were in existence. And in both cases, they were much warmer in 1998.

Okanagan Centre averaged 23.3°C in 2017 and 24.2°C in 1998. Similarly, the Kelowna airport averaged 20.6°C in 2017 versus 21.1°C in 1998.



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The True Source of Religious Discrimination in Canada

How the Patriarchy Promotes Religious Discrimination, Hate, and Violence

by Every 3rd Day Feminism

You will hear people say that “correlation does not imply causation” as if strong correlation has nothing to do with causation, but make no mistake about it, these people who invoke this phrase are ignorant about their white privilege. They will share endless memes about eating pork and loving bacon without realizing the very act of sharing insensitive memes causes violence and oppression toward the the most vulnerable groups in society.

I opened up Facebook today only to discover yet another hateful meme:


Not only is this meme offensive to vegans, it’s disgusting and hurtful to Muslims and Jews. You may as well post the N-word all over your Facebook for your black friends to discover.

The Patriarchy in Canada hates women and non-Christians. It’s not that they love bacon more than other types of food, but rather, they just want to promote Islamophobia and other forms of nativist bigotry against the most vulnerable of Canadians; pork  is the most effective way to viciously malign minorities.

The Patriarchy is a subconscious force in society. So deep in the subconscious that it’s almost too subtle to detect. Thus, most of us don’t even realize we’re promoting hate and violence when we share bacon memes.

The damage from bacon bigotry is far worse that anyone realizes. If we scale for population, 96% of all religious hate crimes in Canada are targeted toward the two religions that don’t eat bacon. This correlation is far too strong to not imply causation. To say otherwise is to say that having 96% of climate scientists agreeing on climate change does not imply they’re right.


You might be thinking that there are other factors, but you’d be wrong. About the only thing exclusive to Jews and Muslims is their dislike of bacon.

The more people share bacon memes, the more discrimination increases. That’s why a recent study showed that hate crimes against Muslims rose by 60% in just one year.

This information should be helpful in your quest for tolerance and understanding. If you remain skeptical of this link between the Patriarchal bacon memes and religious discrimination, then you need to check your privilege.

The people at Cosmopolitan have checked their privilege. They know that whenever tragedy strikes, they need to find ways to promote Muslims in a positive light, not malign them with bacon memes. Go, and do likewise.



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It’s Been so Dry in British Columbia this Year that the Relative Humidity is Literally Off the Charts!


June is typically the wettest month of the year in much of the interior of BC, but not in 2017. The month that is typified by unstable air, thunderstorms, and rain produced a rainless month for much of the Chilcotin and very little elsewhere in southern British Columbia.

2017 was beyond normal, especially on June 26th when a freak meteorological event pushed the relative humidity below 16% over a wide area several hundred kilometers across. One forestry station at Lone Butte even measured 1%!

This would be world record territory… but, did it really happen?

Before answering that, understand that most weather records never actually happened, not necessarily at individual stations, but at the level of states and provinces. For example, Ontario’s all-time record cold never happened nor did Newfoundland and Labrador’s all-time high temperature (I will explain why at a future date).

And those are temperature records, which are some of the more reliable variables we measure. Precipitation records, snow records, wind records, sunshine records, and others are all subject to error.

Humidity is especially problematic because automated weather stations do no have sensors that can reliably measure the relative humidity below 10%.

That’s not usually a problem since relative humidity readings below 16% are quite rare. If it does happen, it’s typically one or two stations, but on the 26th no less than 17 stations fellow below 16%, and many of those below 10%.

The air was so dry, it was literally off the charts. The humidity map below was generated from BC Forest Service weather stations which snapshots the data at 1pm PDT. Places like Alexis Creek recorded 7% for the day, but the lowest of the lot was Lone Butte which bottomed out at 1%.



What is relative humidity?

Relative humidity is basically a measure of the difference between the air temperature and the dew point. Dew point is an expression of the actual (not relative) moisture content of the air. Because air can hold more moisture as it warms, relative humidity drops even as the amount of moisture in the air stays the same. That’s why the relative humidity can be 100% in the morning and 30% in the afternoon without the amount of moisture in the air changing. Similarly, 30% humidity in the summer contains much more moisture in the air than 30% humidity in the winter. Actually, cold winter air is very dry even if it’s at 100%. In other words, when someone tries to tell you that cold moist air along the ocean “feels” colder than interior dry air at the same temperature, they’re mistaken. There’s almost no moisture in the air in either case, and certainly not enough to be able to physically detect. The reason it might “feel” colder on the coast is that there’s more wind.

Environment Canada has a number of stations around the red zone above, but instead of recording the relative humidity, stations will report an error when the temperature difference between the air and dew point is above a certain level. This is because Environment Canada is more concerned with accuracy than Forestry, and since extremely low humidity falls outside of the instrument’s specifications, the number is considered invalid. Given past and current measurements, it seems that the cut-off is 7% humidity.


The above map reveals that drawing a line from Lillooet to Clearwater cuts through an area entirely below 10%, but there are a number of reasons to question any measurement as reliable in that range. Chief among them is that hygrometers are glitchy below 10%.

Skipping Lillooet and Clearwater, I will just focus on Ashcroft and the two Clinton stations. Ashcroft is the most arid place in Canada with very low relative humidity in the summer afternoons, and the nearby village of Clinton has two stations, one of which measured 7% without breaking the hygrometer.

On a normal day the dew point remains stable throughout the day because the moisture in the air remains constant, but on June 26th, the dew point dropped 10 degrees in a single hour at Clinton. The other stations stopped working during the heat of the day because the air was too dry, but it stands to reason their dew points were similar.


Ashcroft is much hotter in the afternoon than Clinton, and especially the airport. This is because Clinton is close to 4,000 feet above sea level versus 1,000 ft for Ashcroft.


Back on May 13th, 2012, Ashcroft measured 7%. That was with a dew point of -10°C and an air temperature of 29°C. On June 26th, 2017, the measurement could not be made, but if we assume the dew point matched Clinton’s -13°C figure, and given the measured air temperature of 35°C, the relative humidity can be calculated to be 4%!

This is definitely possible, and would perhaps be a Canadian record, but how about the 1% reading at Lone Butte? Unlike Ashcroft, the plateau on which Lone Butte sits is not arid or semi-arid, so it’s almost certain that this value is fake. It’s more reasonable to peg the number at 7% because the elevation is similar to the Clinton airport. Even still, that’s almost unbelievable at that elevation and latitude.

As we enter into July, we are extremely dry under the scorching sun with high and extreme fire danger across the province, and yet, not a single weather station is recording relative humidity under 16%. That goes to show you how rare and unusual the June 26th event happened to be.



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